Double columnar transposition + repeating-key Vigenere (widths 5-7, plus 7x8 and 8x7)

Every column order for each width pair, key lengths 3 to 15, with the Vigenere step applied before both column shuffles

In plain English: Every column order for each width pair, key lengths 3 to 15, with the Vigenere step applied before both column shuffles, using two rounds of columnar transposition applied back-to-back. Every combination within the stated scope was tested (1.2 billion configurations); none produced a valid solution. Best match: 15/24 known letters, a level that searches like this can reach without the right key. This record is negative within the tested scope.

NOISE Tier 2

How to read this record

Verdict – ELIMINATED (ruled out within the tested scope), NOISE (nothing beyond what chance produces for a search of this size; also shown when a record stored no verdict of its own), INCONCLUSIVE (the test left candidates or options standing, or could not decide, so it does not rule the method out), INTERESTING (slightly above random, almost certainly coincidence), SIGNAL (statistically unusual, warrants investigation), or FULL MATCH (all 24 known letters correct).
Confidence Tier – Tier 1 = mathematical proof, valid while its stated assumptions hold. Tier 2 = every possibility within the stated scope tested. Tier 3 = partially tested or sampled. Tier 4 = not yet properly tested.
Configs Tested – How many different key/parameter combinations were tried.
Best Score – How many of the 24 known plaintext letters the best attempt matched (out of 24). N/A means no such score could be read from this record.
Keystream Consistency (Bean) – Whether the key values at different positions are mathematically consistent with each other. The check only holds when the known letters stay in their carved positions (no letters rearranged or removed), and the full set used here assumes the standard A to Z alphabet.
Scope Limitations – What this elimination does not rule out.

Configs Tested: 1,200,000,000
Best Score: 15 / 24 known letters matched · can occur by chance in searches like this
Confidence: Tier 2: Exhaustive search under stated assumptions. Does not eliminate multi-layer variants.
Date Tested: 2026-02-15
Script: scripts/transposition/columnar/e_s_06_double_columnar.py

Scope Limitations

This elimination does not rule out:

Covers only width pairs 5x5 to 7x7 plus 7x8 and 8x7. Does not cover Beaufort, other width pairs, or other layer orders.

Assumptions

Vigenere applied first, then two columnar transpositions
Repeating key of length 3 to 15
Standard A-Z alphabet

Reproduce

PYTHONPATH=src python3 -u scripts/transposition/columnar/e_s_06_double_columnar.py

Requires the kryptos repo, Python 3.11+, PYTHONPATH=src. Some recent scripts may not be in the public repository yet.

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